mCry3A delta-endotoxin is a synthetic, maize optimized, modified
cry3A (mcry3A) gene whose expression produces a mCry3A insect
control protein that is a member of a class of proteins which occur
naturally in the gram-positive soil bacterium Bacillus
thuringiensis subsp. tenebrionis.
Additional changes in this maize-optimized gene were made, such
that the mCry3A protein has enhanced activity against the western
corn rootworm and other related pests: (1) its N-terminus
corresponds to methionine-48 of the native protein and (2) a
cathepsin-G protease recognition site has been introduced,
beginning at amino acid residue 155 of the native protein. This
cathepsin-G recognition site has the sequence
alanine-alanine-proline-phenylalanine, and has replaced the amino
acids valine-155, serine-156, and serine-157 in the native protein.
The consensus recognition site for cathepsin-G was determined to be